Devices and methods for delivering energy to body lumens

ABSTRACT

A medical device is disclosed for delivering energy to a body lumen. The device includes an elongate member including a proximal portion and a distal portion adapted for insertion into a body lumen; and an energy delivery device disposed adjacent the distal portion of the elongate member, the energy delivery device including at least one elongate electrode arm, wherein the elongate electrode arm is configured to transition between a first configuration and a second configuration different than the first configuration. The at least one elongate electrode arm includes an active region configured to contact and deliver energy to the body lumen. When the elongate electrode arm is in the first configuration, at least a portion of the active region of the elongate electrode arm extends radially inward toward a longitudinal axis of the energy delivery device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from U.S. ProvisionalApplication No. 61/722,499, filed on Nov. 5, 2012, the entirety of whichis incorporated by reference herein.

TECHNICAL FIELD

Various embodiments of the present disclosure relate generally tomedical devices and related methods. More specifically, particularembodiments of the present disclosure relate to devices and methods fordelivering energy to a body lumen.

BACKGROUND

Asthma is a disease in which (i) bronchoconstriction, (ii) excessivemucus production, and/or (iii) inflammation and swelling of airways canoccur, potentially causing widespread but variable airflow obstruction,thereby making it difficult for the asthma sufferer to breathe. Asthmais a chronic disorder, primarily characterized by persistent airwayinflammation. However, asthma is further characterized by acute episodesof additional airway narrowing via contraction of hyper-responsiveairway smooth muscle.

Asthma may be managed pharmacologically by, among other things: (1)long-term control through use of anti-inflammatories and long-actingbronchodilators, and (2) short-term management of acute exacerbationsthrough use of short-acting bronchodilators. Both of these approachescan require repeated and regular use of the prescribed drugs. High dosesof corticosteroid anti-inflammatory drugs can have serious side effectsthat require careful management. In addition, some patients areresistant to steroid treatment. The difficulty involved in patientcompliance with pharmacologic management and the difficulty of avoidingstimulus that triggers asthma are common barriers to successful asthmamanagement.

Current management techniques are neither completely successful nor freefrom side effects. Presently, a new treatment for asthma is showingpromise. This treatment comprises the application of energy to theairway smooth muscle tissue. Additional information about this treatmentmay be found in commonly assigned patents and applications, includingU.S. Pat. Nos. 6,411,852 and 6,634,363, and U.S. Published ApplicationNos. US-2005-0010270-A1 and US-2002-0091379-A1, the entirety of each ofwhich is incorporated herein by reference.

The application of energy to airway smooth muscle tissue, when performedvia insertion of a treatment device into the bronchial passageways,requires, among other things, navigation through tortuous anatomy (e.g.,curved lung passages) as well as the ability to treat a variety of sizesof bronchial passageways. As discussed in the above referenced patentsand applications, use of an RF energy delivery device is one means oftreating smooth muscle tissue within the bronchial passageways.

FIG. 1 illustrates an exemplary bronchial tree 90. As noted herein,devices treating areas of the lungs must have a construction thatenables navigation through the tortuous airway passages. As shown, thevarious bronchioles 92 extend from right and left bronchi 94, anddecrease in size and have many branches 96. Accordingly, an efficienttreatment requires devices that are be to treat airways of varying sizesas well as function properly when repeatedly deployed after navigatingthrough the tortuous anatomy.

Tortuous anatomy also poses challenges when the treatment devicerequires mechanical actuation of the treatment portion (e.g., expansionof a treatment element at a remote site). In particular, attempting toactuate a member may be difficult in view of the fact that the forceapplied at the operator's hand-piece must translate to the distal end ofthe device. The strain on the operator is further intensified given thatthe operator must actuate the distal end of the device many times totreat various portions of the anatomy. When a typical device iscontorted after being advanced to a remote site in the lungs, theresistance within the device may be amplified given that internalcomponents are forced together.

In addition to basic considerations of navigation and site access, thereexists the matter of device orientation and tissue contact at thetreatment site. Many treatment devices make contact or are placed inclose proximity to the target tissue. Yet, variances in the constructionof the treatment device may hinder proper alignment or orientation ofthe device. For example, in the case of a device having an expandablebasket-type energy delivery element that is deployed intralumenally, thetreatment area may benefit from uniform contact of basket elementsaround the perimeter of the lumen. However, in this case, design ormanufacturing variances may tend to produce a device where the anglebetween basket elements may not be uniform. This problem tends to beexacerbated after repeated actuation of the device and/or navigating thedevice through tortuous anatomy when the imperfections of the devicebecome worsened through plastic deformation of the individualcomponents.

For many treatment devices, the distortion of the energy deliveryelements might cause variability in the treatment effect. For example,many RF devices heat tissue based on the tissue's resistive properties.Increasing or decreasing the surface contact between the electrode andtissue often increases or decreases the amount of current flowingthrough the tissue at the point of contact. This directly affects theextent to which the tissue is heated. Similar concerns may also arisewith resistive heating elements, devices used to cool the airway wall byremoving heat, or any energy delivery device. In any number of cases,variability of the energy delivery/tissue interface may causevariability in treatment results. The consequential risks range from anineffective treatment to the possibility of patient injury.

Furthermore, most medical practitioners recognize the importance ofestablishing acceptable contact between the energy delivery element andtissue. Therefore, distortion of the energy delivery element or elementsincreases the procedure time when the practitioner spends an inordinateamount of time adjusting a device to compensate for or avoid suchdistortion. Such action becomes increasingly problematic in those caseswhere proper patient management limits the time available for theprocedure.

For example, if a patient requires an increasing amount of medication(e.g., sedatives or anesthesia) to remain under continued control forperformance of the procedure, then a medical practitioner may limit theprocedure time rather than risk overmedicating the patient. As a result,rather than treating the patient continuously to complete the procedure,the practitioner may plan to break the procedure in two or moresessions. Subsequently, increasing the number of sessions posesadditional consequences on the part of the patient in cost, the residualeffects of any medication, adverse effects of the non-therapeuticportion of the procedure, etc.

In view of the above, the present methods and devices described hereinprovide an improved means for treating tortuous anatomy such as thebronchial passages. It is noted that the improvements of the presentdevice may be beneficial for use in other parts of the anatomy as wellas the lungs.

SUMMARY

In accordance with certain embodiments of the present disclosure, amedical device is disclosed for delivering energy to a body lumen. Thedevice includes an elongate member including a proximal portion and adistal portion adapted for insertion into a body lumen; and an energydelivery device disposed adjacent the distal portion of the elongatemember, the energy delivery device including at least one elongateelectrode arm, wherein the elongate electrode arm is configured totransition between a first configuration and a second configurationdifferent than the first configuration. The at least one elongateelectrode arm includes an active region configured to contact anddeliver energy to the body lumen, wherein the active region is disposedbetween a proximal end region and a distal end region of the elongateelectrode arm. When the elongate electrode arm is in the firstconfiguration, at least a portion of the active region of the elongateelectrode arm extends radially inward toward a longitudinal axis of theenergy delivery device.

In accordance with certain embodiments of the present disclosure, amedical device is disclosed for delivering energy to a passageway of apatient's lung. The device includes an elongate member having a proximalend, a distal end, and a lumen extending therebetween; and a basketassembly adjacent the distal end and configured to transition between acollapsed state and an expanded state, wherein the basket assemblyincludes a plurality of expandable legs, wherein at least one of theexpandable legs includes an active region configured to contact anddeliver energy to a wall of the passageway when the basket assembly isin the expanded state. When the basket assembly is in the collapsedstate, at least a portion of the active region of the at least one ofthe expandable legs includes an inwardly concave configuration.

In accordance with certain embodiments of the present disclosure, amedical device is disclosed for delivering energy to a body lumen. Thedevice includes a flexible elongate member comprising a proximal portionand a distal portion adapted for insertion into a body lumen; and anenergy delivery device disposed adjacent the distal portion of theelongate member, the energy delivery device comprising at least oneelongate electrode and being configured to move between an expandedstate and a collapsed state. The at least one elongate electrodecomprises an active region configured to contact and deliver energy tothe body lumen when the energy delivery device is in the expanded state.When the energy delivery device is in the collapsed state, at least aportion of the active region of the elongate electrode bows radiallyinward toward a longitudinal axis of the energy delivery device, suchthat at least a portion of the active region is closer to thelongitudinal axis than at least a portion of the proximal adjoiningregion and at least a portion of the distal adjoining region. Upon theapplication of axial compressive forces to the elongate electrode, theelongate electrode is configured to bow outward away from thelongitudinal axis of the energy delivery device.

The disclosed embodiments may include one or more of the followingfeatures: the at least one elongate electrode arm may include aplurality of elongate electrode arms; the plurality of elongateelectrode arms may be secured together to form a basket assembly; thebasket assembly may be self-expandable; the elongate electrode arm maybe configured to transition from the first configuration to the secondconfiguration when an axially compressive force is applied to theelongate electrode arm; when the elongate electrode arm is in the firstconfiguration, the elongate electrode arm may include a substantiallyconcave configuration; when the elongate electrode arm is in the secondconfiguration; the active region of the elongate electrode arm mayinclude a substantially planar configuration; a member configured toapply an axially compressive force to the at least one elongateelectrode; the at least one elongate electrode arm may be formed of ashape memory material; the proximal end region and the distal end regionof the elongate electrode arm may include an insulating coating; theactive region may include an electrode secured to the elongate electrodearm; the active region may include an electrode secured to the at leastone expandable leg; when the basket assembly is in the expandedconfiguration, the active region of the at least one of the expandablelegs may include a substantially planar configuration; the active regionof the at least one of the expandable legs may be disposed between aproximal leg portion and a distal leg portion; the proximal and distalleg portions may include an insulating coating; the proximal adjoiningregion and the distal adjoining region are either substantially flat orbow radially inward toward the longitudinal axis of the energy deliverydevice; when the energy delivery device is in the expanded state, theactive area becomes substantially planar, and at least a portion of theactive region becomes positioned farther from the longitudinal axis thanat least the portion of the proximal adjoining region and at least theportion of the distal adjoining region: the at least one elongateelectrode comprises a plurality of elongate electrodes that form anexpandable basket assembly.

The present disclosure describes devices configured to treat the airwaysor other anatomical structures, and may be especially useful in tortuousanatomy. The devices described herein are configured to treat withuniform or predictable contact (or near contact) between an activeelement and tissue. Typically, the disclosed devices allow this resultwith little or no effort by a physician. Accordingly, aspects of thedisclosed embodiments offer increased effectiveness and efficiency incarrying out a medical procedure. The increases in effectiveness andefficiency may be especially apparent in using devices having relativelylonger active end members.

In view of the above, a variation of the disclosed device includes acatheter for use with a power supply, the catheter comprising a flexibleelongate shaft coupled to at least one energy delivery element that isadapted to apply energy to the body lumen. The shaft will have aflexibility to accommodate navigation through tortuous anatomy. Theenergy delivery elements are described below and include basket typedesign, or other expandable designs that permit reduction in size orprofile to aid in advancing the device to a particular treatment siteand then may be expanded to properly treat the target site. The baskettype designs may be combined with expandable balloon or other similarstructures.

Variations of the device can include an elongate sheath having a nearend, a far end adapted for insertion into the body, and having aflexibility to accommodate navigation through tortuous anatomy, thesheath having a passageway extending therethrough, the passageway havinga lubricious layer extending from at least a portion of the near end tothe far end of the sheath, where the shaft is slidably located withinthe passageway of the sheath.

Variations of devices described herein can include a connector forcoupling the energy delivery element to the power supply. The connectormay be any type of connector commonly used in such applications.Furthermore, the connector may include a cable that is hard-wired to thecatheter and connects to a remote power supply. Alternatively, theconnector may be an interface that connects to a cable from the powersupply.

Variations of the device allow for reduced friction between the shaftand sheath to allow relatively low force advancement of a distal end ofthe shaft out of the far end of the sheath for advancement the energydelivery element. Additional variations of the disclosed embodimentsinclude devices allowing for repeatable deployment of the expandableenergy delivery element while maintaining the orientation and/or profileof the components of the energy delivery element. One such exampleincludes an energy delivery basket comprising a plurality of arms, eacharm having a distal end and a proximal end, each arm having a flexurelength that is less than a full length of the arm.

An additional variation of the device includes a catheter for use intortuous anatomy to deliver energy from a power supply to a bodypassageway. Such a catheter includes an expandable energy deliveryelement having a reduced profile for advancement and an expanded profileto contact a surface of the body passageway and an elongate shaft havinga near end, a far end adapted for insertion into the body, theexpandable energy delivery element coupled to the far end of the shaft,the shaft having a length sufficient to access remote areas in theanatomy. The design of this shaft includes column strength sufficient toadvance the expandable energy delivery element within the anatomy, and aflexibility that permits self-centering of the energy delivery elementwhen expanded to contact the surface of the body passageway.

Additional objects and advantages of the disclosed embodiments will beset forth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of thedisclosed embodiments. The objects and advantages of the disclosedembodiments will be realized and attained by means of the elements andcombinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosed embodiments, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various exemplary embodiments andtogether with the description, serve to explain the principles of thedisclosed embodiments.

FIG. 1 is an illustration of a person's bronchial passageways;

FIG. 2 is a diagram of an exemplary energy delivery system consistentwith embodiments of the present disclosure;

FIG. 3 is a diagram of an exemplary energy delivery device consistentwith embodiments of the present disclosure;

FIG. 4 is a diagram of an exemplary energy delivery device disposed in aperson's bronchial passageway;

FIG. 5 is a cross-sectional diagram of an exemplary energy deliverydevice;

FIGS. 6A-6B depict exemplary pre-shaped energy delivery electrode wires;

FIGS. 7A-7B depict exemplary pre-shaped energy delivery electrode wiresconsistent with embodiments of the present disclosure;

FIGS. 8A-8B depict exemplary pre-shaped energy delivery electrode wiresconsistent with embodiments of the present disclosure;

FIG. 9 depicts a fixture for molding a pre-shaped enemy deliveryelectrode, consistent with embodiments of the present disclosure; and

FIG. 10 depicts a cross-sectional diagram of an exemplary energydelivery device consistent with embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

It is understood that the examples below discuss uses in the airways ofthe lungs. However, unless specifically noted, the disclosed embodimentsare not limited to use in the lung. Instead, the disclosed embodimentsmay have applicability in various parts of the body, including, but notlimited to, urological, biliary, and gastrointestinal applications.Moreover, the disclosed embodiments may be used in various procedureswhere the benefits of the device are desired.

FIG. 2 shows a schematic diagram of one example of a system 10 fordelivering therapeutic energy to tissue of a patient for use with thedevice described herein. The illustrated variation shows the system 10having a power supply (e.g., consisting of an energy generator 12), acontroller 14 coupled to the energy generator, and a user interfacesurface 16 in communication with the controller 14. It is noted that thedevice may be used with a variety of systems (having the same ordifferent components). For example, although variations of the deviceshall be described as RF energy delivery devices, some embodiments ofthe device may include resistive heating systems, infrared heatingelements, microwave energy systems, focused ultrasound, cryo-ablation,or any other energy system. It is noted that the devices describedshould have sufficient length to access the tissue targeted fortreatment. For example, it is presently believed necessary to treatairways as small as 3 mm in diameter to treat enough airways for thepatient to benefit from the described treatment (however, it is notedthat the disclosed embodiments are not limited to any particular size ofairways and airways smaller or larger than 3 mm may be treated with theembodiments disclosed herein). Accordingly, devices for treating thelungs must be sufficiently long to reach deep enough into the lungs totreat these airways. Accordingly, the length of the sheath/shaft of thedevice that is designed for use in the lungs may be between 1.5-3 ft.long in order to reach the targeted airways.

The particular system 10 depicted in FIG. 2 is one having a userinterface as well as safety algorithms that are useful for the asthmatreatment discussed above. Additional information on such a system maybe found in U.S. Provisional application No. 60/674,106, filed Apr. 21,2005, entitled CONTROL METHODS AND DEVICES FOR ENERGY DELIVERY, theentirety of which is incorporated by reference herein.

Referring again to FIG. 2, a variation of a device 100 described hereinincludes a flexible sheath 102, an elongate shaft 104 (in this example,the shaft extends out from the distal end of the sheath 102), and ahandle or other operator interface 106 (optional) secured to a proximalend of the sheath 102. The distal portion of the device 100 includes anenergy delivery element 108 (e.g., an electrode, a basket electrode, aresistive heating element, cyroprobe, etc.). Additionally, the device100 includes a connector 110 common to such energy delivery devices. Theconnector 110 may be integral to the end of a cable 112 as shown, or theconnector 110 may be fitted to receive a separate cable 112. In anycase, the device may be configured for attachment to the power supplyvia some type connector 110. The elongate portions 102, 104 of thedevice 100 may also be configured and sized to permit passage throughthe working lumen of a commercially available bronchoscope or endoscope.As discussed herein, the device 100 is often used within an endoscope,bronchoscope, or similar device. However, the device 100 may also beadvanced into the body with or without a steerable catheter, in aminimally invasive procedure or in an open surgical procedure, and withor without the guidance of various vision or imaging systems.

FIG. 2 also illustrates additional components used in variations of thesystem 10. Although the depicted systems are shown as RF-type energydelivery systems, it is noted that the disclosed embodiments are notlimited as such. Other energy delivery configurations contemplated mayinclude or not require some of the elements described below. The powersupply (usually the user interface portion 16) shah have connections 20,28, 30 for the device 100, return electrode 24 (if the system 10 employsa monopolar RF configuration), and actuation pedal(s) 26 (optional). Thepower supply and controller may also be configured to deliver RF energyto an energy delivery element configured for bipolar RF energy delivery.The user interface 16 may also include visual prompts 32, 60, 68, 74 foruser feedback regarding setup or operation of the system. The userinterface 16 may also employ graphical representations of components ofthe system, audio tone generators, as well as other features to assistthe user with system use.

In many variations of the system, the controller 14 may include aprocessor 22 that is generally configured to accept information from thesystem and system components, and process the information according tovarious algorithms to produce control signals for controlling the energygenerator 12. The processor 22 may also accept information from thesystem 10 and system components, process the information according tovarious algorithms and produce information signals that may be directedto the visual indicators, digital display or audio tone generator of theuser interface in order to inform the user of the system status,component status, procedure status or any other useful information thatis being monitored by the system. The processor 22 of the controller 14may be a digital IC processor, analog processor, or any other suitablelogic or control system that carries out the control algorithms, such asthose described in U.S. Provisional application No. 60/674,106, filedApr. 21, 2005, entitled CONTROL METHODS AND DEVICES FOR ENERGY DELIVERY,the entirety of which is incorporated by reference herein.

FIG. 2 illustrates one example of an energy delivery element 108. Inthis example, the energy delivery element 108 includes a “basket”-likeconfiguration that implements actuation for expansion of the basket indiameter via a slide mechanism 114 on the handle 106. For example, anoperator may manipulate slide mechanism 114, which, through some type oflinkage, causes electrode wires of energy delivery element 108 to expandradially outward or otherwise mechanically deploy. Alternatively, thebasket may be configured to expand as soon as it is exposed by a sheath,due to its own resilient forces (i.e., making it “self-expandable”).Such features may be useful when the device is operated intralumenallyor in anatomy such as the lungs due to the varying size of the bronchialpassageways that may require treatment.

FIG. 3 illustrates an embodiment in which device 100 may be advancedthrough a working channel 33 of a bronchoscope 18. While a bronchoscope18 may assist in the procedure, the device 100 may be used throughdirect insertion or other insertion means as well. In addition, FIG. 3illustrates an embodiment of energy delivery element 108 in a basketconfiguration and including a number of arms 120 that carry electrodes(not shown). In this embodiment, the arms 120 are attached to theelongated shaft 104 at a proximal end while the distal end of the arms120 are affixed to a distal tip 122. In one embodiment, the arms 120 maybe “tipless”, whereby the arms 120 do not terminate in distal tip 120but instead “double back” on themselves, forming one or more loopswithin distal tip 122. To actuate the energy delivery element 108, awire or tether 124 may be affixed to the distal tip 122 to enablecompression of the arms 120 between the distal tip 122 and elongateshaft 104. When the energy delivery element 108 is actuated, i.e.,expanded, the arms 120 may bow outward, away from a longitudinal axis ofthe energy delivery element 108.

FIG. 4 depicts an example of device 100, including energy deliveryelement 108, being advanced thorough a body lumen 92, e.g., a bronchialpassageway. In one embodiment, as shown in FIG. 4, device 100 may alsoincorporate a junction 176 that adjusts for misalignment between thebranching airways or other body passages, thereby allowing alignment ofthe device to closely match the alignment of the airway. It is notedthat the present feature also benefits those cases in which the pathwayand target site are offset as opposed to having an angular difference.The junction 176 helps to eliminate the need for alignment of the axisof the active element 108 with the remainder of the device in order toprovide substantially even tissue contact. The junction may be a joint,a flexure, or equivalent means. FIG. 4 illustrates an example of wherethe access passageway and passageway to be treated are misaligned by anangle alpha (α). Yet, the energy delivery element 108 of the treatmentdevice 100 remains substantially aligned with the target area.

FIG. 5 depicts an embodiment of energy delivery element 108 in acollapsed configuration (electrode arms 120A) and expanded configuration(electrode arms 1208). Specifically, the electrode arms of energydelivery element 108 may be originally shaped like electrode arms 120A,as shown in FIG. 5, when energy delivery element 108 is in a collapsedconfiguration. The electrode arms may be deformed to the shape ofelectrode arms 120B.

FIG. 5 depicts an embodiment of energy delivery element 108 including arepresentation of an active region 50. Active region 50 of electrodearms 120A/120B may be a conductive region of electrode arms 120A/120B.For example, the electrodes may be generally metallic or otherwiseconductive, and have an insulator disposed around the electrodes in allareas other than the active region 50. Alternatively, electrode arms120A/120B may have a special metallic coating or other conductivematerial applied to electrode arms 120A/120B around the active region50. As discussed above, the active region 50 may be configured tocontact and apply energy to the tissue of a body lumen. In the energydelivery element 108 of FIG. 5, the initial shape of collapsed electrodearms 120A, and therefore the resulting shape of expanded electrode arms120B, may cause only a subset of active region 50 to contact and applyenergy to the body lumen tissue. In other words, the “contact area” maybe generally shorter than desired, and/or less of the active region 50than desired.

Electrode arms 120A/B of the energy delivery element 108 may havevarious cross-sectional shapes. For example, the shapes may be round,rounded or polygonal in cross section. Additionally, each electrode armmay change cross section along its axis, providing for, for example,electrodes that are smaller or larger in cross section than the distaland proximal portions of each electrode arm. This would provide avariety of energy delivery characteristics and bending profiles,allowing the design to be improved such that longer or wider electrodeconfigurations can be employed. For example, if the cross-sectionalthickness of the active portion of the electrode arm is greater than thecross-sectional thickness of the distal and proximal (i.e., inactive)portions of the electrode arm, the electrode arm would be predisposed tobow outward in the distal and proximal sections, while remaining flatterin the active area of the electrode arm, potentially providing improvedtissue contact.

One objective of the present disclosure involves increasing the amountof active region 50 that contacts a body lumen, e.g., to promote moreuniform contact between the energy delivery elements 108 and a treatedbody lumen. Another objective of the present disclosure involvesincreasing the ratio of the contact area to the active region 50; and/ora ratio of the contact area to the electrode length 55. Traditionally,the active region 50 may be substantially curved along its entirelength, causing only around 5 mm of the active region 50 to constitute“contact area” with the body lumen. For example, traditional energydelivery elements 108 may form a shape that is naturally formed by astraight wire that is compressed or otherwise urged to bow outwardlynear its midpoint. Accordingly, in one exemplary embodiment, electrodearms 120 of energy delivery element 108 may be pre-bent or pre-shapedbefore being expanded into a basket configuration.

Referring now to FIGS. 6A-8B, the electrode arms of energy deliveryelement 108 may be pre-shaped as already described herein. Inparticular, the electrode arms 120 may be pre-shaped to control thedirection in which the arms deflect upon basket deployment 108 toprevent electrode inversion, provide controlled buckling of the basketelectrode 108, and improve tissue contact.

FIG. 6A illustrates a pre-bent electrode arm 600, which is pre-bentaccording to existing techniques. For example, the electrodes may beconstructed of a suitable current conducting metal or alloys such as,for example, copper, steel, and platinum. The electrodes may also beconstructed of a shape memory alloy which is capable of assuming apredetermined, i.e., programmed, shape upon reaching a predetermined,i.e., activation, temperature. Such metals are known in the art asdescribed, for example, in U.S. Pat. Nos. 4,621,882 and 4,772,112, whichare incorporated herein. For the presently disclosed embodiments, theshape memory metal used may have the characteristic of assuming adeflection away (La, expands) from a device longitudinal axis whenactivated, i.e., heated in excess of the normal body temperature andpreferably between 60° C. and 95° C. One suitable shape memory alloy isavailable as NITINOL from Raychem Corp., Menlo Park, Calif.

As shown in FIG. 6B, when axial compressive loads are applied to theelectrode 600 during deployment, the pre-shaped arm is predisposed tobuckle or deflect in a predictable, desired outwards direction intoelectrode arm 600′, to make contact with the airway wall. Hence, thepre-shaped arm 600 provides for preferential buckling in the outwarddirection, thereby forming expanded electrode arm 600′, which is of usein tortuous airways where orthogonal or side loads commonly cause arminversions. At all points along its length, the pre-shaped arm 600 iseither straight or bows outward from a longitudinal axis of an energydelivery element. However, as described above, the configuration of FIG.6A-6B may result in a tissue contact area of expanded electrode arm 600′that is shorter and less uniform than desired, and/or a smallerproportion of active area 50 than desired.

Accordingly, several alternative pre-shaped electrode arms aredisclosed, which may be employed to induce more desirable bowing orbuckling upon the application of axial compression, so that an entireactive area may make contact with a patient's tissue. FIG. 7A depicts anembodiment of a pre-shaped electrode arm 700 having an active area 702that bows inward toward a longitudinal axis of the energy deliverydevice, when in a collapsed configuration. In other words, the activearea 702 is pre-shaped to be convex from a perspective of thelongitudinal axis of the energy delivery device, and concave from aperspective away from the energy delivery device. As a result of theconcavity, or inward bowing, of active area 702, axial compressiveforces on electrode arm 700 cause electrode arm 700 to deform to theshape depicted as electrode arm 700′ of FIG. 7B. Specifically, asdepicted in FIG. 7B, axial compressive forces on electrode arm 700 causethe electrode arm 700, including concave active area 702, to form anexpanded electrode arm 700′ having a desirable active area 702′. Concaveactive area 702 may flatten to form a substantially flat active area702′ by virtue of torque transferred from end portions of electrode arm700 to the concave active area 702, upon the application of axial forces(e.g., from wire or tether 124 applying tension, as described above).

By comparison between FIGS. 6B and 7B, it can be seen that expandedelectrode arm 700′ may form a longer and more uniform contact area ascompared to the contact area of expanded electrode arm 600′. Inaddition, expanded electrode arm 700′ may form a flatter active area700′ than the active area of expanded electrode arm 600′, thereby alsocausing longer, and more uniform contact area. In one embodiment, thecontact area of expanded electrode arm 700′ may be approximately 5-15 mmin length. Because of the pre-formed concavity in electrode arm 700, theshape of active area 702 on expanded electrode arm 700, and resultinglengthened contact area, may promote more uniform contact between thedevice active area 702′ and the tissue targeted for energy delivery. Forexample, the shape of expanded electrode arm 700′ may provide desirableand consistent tissue contact over a substantial entirety of active area702.

FIG. 8A depicts an electrode arm 800 having a flat active area 802 andconcave adjoining portions 804. As a result of the concavity, or inwardbowing, of adjoining portions 804, axial compressive forces on electrodearm 800 may cause electrode arm 800 to deform to the shape depicted aselectrode arm 800, as shown in FIG. 8B. Specifically, as depicted inFIG. 8B, axial compressive forces on electrode arm 800 causes theelectrode arm 800; including concave adjoining portions 804, to form anexpanded electrode arm 800′ having an active area 802. Concave adjoiningportions 804 may expand to form longer active area 802′ by virtue oftorque transferred from end portions of electrode arm 800 to active area802 and adjoining portions 804, upon the application of axial forces(e.g., from wire or tether 124 applying compression, as describedabove).

By comparison between FIGS. 6B and 8B, it can be seen that expandedelectrode arm 800′ may form a longer and more uniform contact area ascompared to the contact area of expanded electrode arm 600′. Inaddition, expanded electrode arm 800′ may form a flatter active area800′ than the active area of expanded electrode arm 600, thereby alsocausing longer, and more uniform contact area. In one embodiment, thecontact area of expanded electrode arm 800′ may be approximately 5-15 mmin length. Because of the pre-formed concavity in adjoining portions ofelectrode arm 800, the shape of active area 802′ on expanded electrodearm 800′, and resulting lengthened contact area, may promote moreuniform contact between the device active area 802′ and the tissuetargeted for energy delivery. For example, the shape of expandedelectrode arm 800′ may provide desirable and consistent tissue contactover a substantial entirety of active area 802′.

FIG. 9 depicts a fixture 900 for making an electrode wire consistentwith the embodiments of the present disclosure, including the pre-shapedelectrode wires of FIGS. 7A and 8A. Specifically, fixture 900 contains aplurality of contours 902 into which a wire may be disposed fordeformation. Contours 902 may contain a concaved portion 904, which mayimpart a concaved feature, e.g., concave portion 702, onto an electrodewire. In one embodiment, a Nitinol ribbon, or other shape memorymaterial, may be set into the contours 902 of fixture 900. A press platemay be used to press the Nitinol ribbon or other wire against thedesired contours formed in the fixture 900. Heat may be applied to thewire to aid in deforming the wire against the contours 902 of fixture900, thereby pre-setting the shape of the wire.

FIG. 10 depicts an embodiment of energy delivery device 108 includingelectrode arms 120A/120B consistent with electrode arm 700/700′ depictedin FIGS. 7A and 7B. FIG. 10 also depicts an embodiment of energydelivery element 108 including a representation of an active region 50.Specifically, the electrode arms of energy delivery element 108 may beoriginally shaped like electrode arms 120A, as shown in FIG. 10, whenenergy delivery element 108 is in a collapsed configuration. Theelectrode arms may be deformed to the shape of electrode arms 120B, bythe application of axial compressive forces. Because the electrode arms120A have concave portions consistent with concave portions 702 of FIG.7A, a larger portion of active region 50 may be in contact with bodylumen tissue, than of the active region depicted in FIG. 5. Moreover,contact area of the active region 50 of FIG. 10 may be a largerproportion of the active region 50 and/or of the overall electrodelength 55, as compared to that of the electrode disclosed in FIG. 5.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1-20. (canceled)
 21. A medical device, comprising: an elongate memberhaving a proximal end and a distal end; and a basket assembly disposedat or adjacent the distal end, the basket assembly being configured totransition between a collapsed state and an expanded state, wherein thebasket assembly includes a plurality of expandable legs, and while inthe collapsed state, a first expandable leg of the plurality ofexpandable legs includes a first region that is convex when viewed froma central longitudinal axis of the medical device, an active regiondisposed distally of the first region, and a second region disposeddistally of the active region, the second region being convex whenviewed from the central longitudinal axis.
 22. The medical device ofclaim 21, wherein the active region is substantially parallel to thecentral longitudinal axis when the basket assembly is in the collapsedstate.
 23. The medical device of claim 21, wherein the first region andthe second region are pre-shaped to be convex when viewed from thecentral longitudinal axis when the basket assembly is in the collapsedstate.
 24. The medical device of claim 21, wherein the first region andthe second region are configured to be convex when viewed from thecentral longitudinal axis while the basket assembly is unconstrained byan outer sheath and in the collapsed state.
 25. The medical device ofclaim 21, wherein, when the basket assembly is in the expanded state,distal ends of the plurality of expandable legs converge toward oneanother.
 26. The medical device of claim 21, wherein portions of thefirst expandable leg proximal and distal to the active region include aninsulating coating.
 27. The medical device of claim 21, wherein theplurality of expandable legs are circumferentially spaced from oneanother about the central longitudinal axis of the medical device. 28.The medical device of claim 21, wherein the plurality of expandable legsare configured to deliver RF energy.
 29. The medical device of claim 21,further including a distal tip, wherein a distal end of each of theplurality of expandable legs is coupled to the distal tip.
 30. Themedical device of claim 29, further including an actuating member thatextends from the distal end of the elongate member, through a volumedefined by the plurality of expandable legs, to the distal tip.
 31. Themedical device of claim 21, wherein the first region, the active region,and the second region together form a portion that is concave whenviewed from the central longitudinal axis when the basket assembly is inthe expanded state.
 32. The medical device of claim 21, wherein thefirst expandable leg includes a shape memory material.
 33. The medicaldevice of claim 21, wherein each of the plurality of expandable legsincludes a first region that is convex when viewed from the centrallongitudinal axis, an active region disposed distally of the firstregion, and a second region disposed distally of the active region, thesecond region being convex when viewed from the central longitudinalaxis.
 34. A medical device, comprising: an elongate member having aproximal end and a distal end; and a basket assembly disposed at oradjacent the distal end, the basket assembly being configured totransition between a collapsed state and an expanded state, wherein thebasket assembly includes a plurality of expandable legs, a firstexpandable leg of the plurality of expandable legs including an activeregion that is flat when the basket assembly is in the collapsed state,and that is concave when viewed from a central longitudinal axis of themedical device when the basket assembly is in the expanded state. 35.The medical device of claim 34, further including a first region that isproximal to the active region and is convex when viewed from the centrallongitudinal axis of the medical device, and a second region disposeddistally of the active region, the second region being convex whenviewed from the central longitudinal axis.
 36. The medical device ofclaim 35, further including: a distal tip, wherein a distal end of eachof the plurality of expandable legs is coupled to the distal tip; and anactuating member that extends from the distal end of the elongatemember, through a volume defined by the plurality of expandable legs, tothe distal tip.
 37. The medical device of claim 36, wherein, when thebasket assembly is in the expanded state, distal ends of the pluralityof expandable legs converge toward one another.
 38. A medical device,comprising: an elongate member having a proximal end and a distal end;and a basket assembly disposed at or adjacent the distal end, the basketassembly being configured to transition between a collapsed state and anexpanded state, wherein the basket assembly includes a plurality ofexpandable legs, wherein a first expandable leg of the plurality ofexpandable legs includes a proximal region, a first region disposeddistally of the proximal region, an active region disposed distally ofthe first region, a second region disposed distally of the activeregion, and a distal region disposed distally of the second region,wherein the first expandable leg is pre-shaped such that in thecollapsed state and while the basket assembly is unconstrained by anouter sheath: the first region extends distally and radially outwardfrom the proximal region; the first region is convex when viewed from acentral longitudinal axis of the medical device; the active region issubstantially parallel to the central longitudinal axis; the secondregion extends distally and radially inward from the active regiontoward the distal region; and the second region is convex when viewedfrom the central longitudinal axis.
 39. The medical device of claim 38,wherein the proximal region is substantially parallel to the centrallongitudinal axis while the basket assembly is in both the collapsedstate and the expanded state.
 40. The medical device of claim 38,wherein the distal region is substantially parallel to the centrallongitudinal axis while the basket assembly is in both the collapsedstate and the expanded state.